A. Field of the Invention
The present invention pertains to dispensing guns, and more particularly, to a readily disassemblable fluid dispensing gun which mixes fluidic components. The dispensing gun employs flexible, fluid transporting tubes which may be quickly replaced or cleaned.
In many manufacturing processes, and specifically in the wood products industry, it is often desirable to mix fluidic materials in order to form putties or glues. For instance, in plywood manufacture, it is desirable to fill knotholes and other defects in the surface of plywood panels with a mixture of resin and catalyst. After a knothole or defect is filled, the plywood surface may be planed or sanded in order to provide a smooth finish. In order to mix resin and catalyst, a device must be provided which sufficiently comingles the materials for delivery through a mixing tube for eventual discharge into a knothole or defect.
Resin and catalyst, when comingled, form a mix which sets up or hardens quite rapidly. Thus, it becomes apparent that when resin and catalyst are to be mixed, the residue must be quickly cleaned from the inside of a dispensing unit if the unit is not to become jammed or clogged. While fluidic dispensing guns are known in the art, a typical defect in these guns is the lack of readily disassemblable components which enable fluidic transporting tubes to be quickly cleaned or replaced.
The present invention contemplates a novel dispensing gun which may be readily disassembled so that fluidic transporting tubes can be replaced or cleaned. Specifically, the present invention provides for a portable, hand-held dispensing gun which includes a handle portion with an upper barrel to which a head assembly is detachably secured at a rear portion thereof. The head assembly extends flexible, fluid transporting tubes through the barrel to a front portion thereof. A cap is detachably secured to the front portion of the barrel for forming an initial mixing chamber. Disposed outwardly from the cap is an elongate tube which may contain a static mixer or the like. Fluidic components to be mixed are introduced from a supply source through hoses to the head assembly and through passages in the head assembly for delivery through tubes to the initial mixing chamber. In order for fluidic components to travel through the tubes, a trigger having a member which normally deforms the tubes to restrict flow therethrough is movable to a nontube contacting position to permit fluid flow therethrough. Disposed adjacent to the fluidic transporting tubes is a solvent tube which will permit the metered passage of solvent to the initial mixing chamber and outwardly through the elongate conduit when a valve is opened to remove resin-catalyst residue.
B. Description of the Prior Art
Guns for dispensing fluidic materials or sprays are well known in the art. For example, in U.S. Pat. No. 2,584,178 there is disclosed a spray gun adapted for spraying a mixture of a liquid or liquids and a gas or gases under pressure onto a surface or an article, whereby to coat or impregnate same. The gun disclosed in this patent is directed to simultaneously spraying two fluids which are maintained in an unmixed condition until they are discharged from the spray nozzle of the gun, whereby the fluids then mix in midair prior to impinging upon a surface or an article. The gun incorporates a lever arm pivotally connected to the gun body to move a further lever arm against a spring biased jaw. As the lever arm is depressed, the spring biased jaw is moved to permit fluids to flow through a plurality of conduits. When the lever is released, the spring biased jaws are moved upwardly against the conduits to deform same and restrict fluid flow therethrough. It is to be specifically noted that the fluids transported through the conduits do not mix until they are passed outwardly through a forwardly arranged nozzle. Furthermore, it is to be noted that the conduits are not readily removable from the gun supporting structure, and there is no provision for a cleaning conduit.
Another prior art spray gun is described in U.S. Pat. No. 2,619,386 and includes a gun adapted to spray two solutions simultaneously. The gun is connected to a source of fluid supply by flexible rubber hoses. A spring biased trigger normally urges a crossbar to a deforming contact position with the flexible rubber hoses to compress same for preventing fluid flow therethrough. Upon depressing the handle actuatable trigger, the crossbar is released from compressing the hoses. Fluid may then flow through the hoses for dispensing outwardly from a nozzle head.
U.S. Pat. No. 2,335,528 sets forth a method of treating lumber in which a means for introducing material under pressure into a recess in the lumber is described. A supply of liquid glue or other cementitious material is disposed above the lumber in an inclined reservoir. A conduit depends from the reservoir to a device which permits the glue under pressure to be discharged into a knothole or other defect. While this patent generally describes a method for treating lumber, the reservoir and trigger valve associated therewith are not portable and furthermore the device does not permit comingling of fluidic materials.
An apparatus for applying putty is disclosed in U.S. Pat. No. 3,775,016. A hand-held troweling tool for applying putty to a workpiece includes a handle and a head assembly secured to the handle. A compressible tube through which putty may be supplied to a cavity in the handle opens into the cavity. A trigger lever on the handle is operable to remove a biasing force against the tube to permit putty flow.
A last prior art device to be considered as being relevant to the present invention is U.S. Pat. No. 3,195,170. Here, there is described a liquid supply system in which an apparatus is designed to supply paint or the like to rollers or brushes. A lever is pivotally connected to a handle through which handle extends a flexible tube from a source of paint. The handle is normally biased against the flexible tube to deform same thereby preventing the flow of paint therethrough. Upon depressing the handle against the spring bias, the tube or hose is permitted to allow paint or the like to flow therethrough to the brushes. It is readily apparent that the tubes and hoses described in this patent are not readily replaceable and furthermore no gun structure is disclosed.